I'd suggest you check out these two threads. Threehorses is an authority on things medical and the other has good basic information.
Threehorses Worm Thread
https://www.backyardchickens.com/forum/viewtopic.php?id=213065&p=1
Florida Worm Page
http://edis.ifas.ufl.edu/pdffiles/VM/VM01500.pdf